Category Archives: Physics

Cathode rays and their 15 properties

Definition of cathode rays: Cathode rays are the group of fast moving negatively charged particles. These negatively charged particles are electrons. These rays are shot out at a high speed from the cathode of a discharge tube at a pressure … Continue reading

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Why laser is needed in holography

As recording process in holography is based on the principle of interference. For recording and for sustained interference, the path difference between various interfering light waves should always be less than longitudinal coherence length. For ordinary light source like mercury … Continue reading

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Reflection and transmission hologram

Reflection hologram: If recording material in hologram is placed such that reference beam and object beam approach it from two opposite sides, then hologram formed is called Reflection Type hologram. The interference fringes are usually parallel to the surfaces of … Continue reading

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Gravitational force and its properties

Gravitational force is the weakest force in nature. There are many properties of gravitational force, but first of all let us discuss about the various fundamental forces present in nature. There are mainly four types of forces exist in nature: … Continue reading

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Einstein Coefficient Relation

Einstein Coefficient Relation derivation and discussion: Einstein showed the interaction of radiation with matter with the help of three processes called stimulated absorption, spontaneous emission and stimulated emission. He showed in 1917 that for proper description of radiation with matter,the … Continue reading

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How does a laser work

One must have seen and if not seen then must have heard the term laser. But if you have seen the laser light emitting from a source, then there should be natural question how does a laser work? Therefore let … Continue reading

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Difference beween holography and photography

Last time I have discussed about the holography and written that it is a two stage process. The first stage is recording of hologram in the form of interference pattern and in the second stage, the hologram acts as a … Continue reading

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Recording and reconstruction process in holography

Last time I have discussed the basic definition of holography and hologram. Today I will discuss the process with the help of which hologram is formed or complete picture is recorded: 1. Recording  of hologram. The recording of hologram  is … Continue reading

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Holography

The word holography originates from the Greek  words “holos” (complete) and “graphos” (writing). Thus, it is the technique to record the complete picture of an object. The technique was  proposed by Gabor in 1947. An ordinary photograph records the two … Continue reading

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Applications of lasers

Lasers have applications in almost every field like medicine, industry, communication and science and technology. These applications are due to the directional, coherent and monochromatic properties of lasers. a) Holography: Holography is a technique to record the complete picture of … Continue reading

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